When playing a part as beloved, well-known and demanding as Tevye in “Fiddler on the Roof,” there are definite dos and don’ts. It is important not to subtract from the character that has given it universal appeal. Tevye is such a cultural icon that it is of paramount importance that he remain recognizable. On the other hand, a large part of what makes Tevye so beloved in the first place is that those who have played him (Topol and Zero Mostel) have imbued the character with so much of themselves. It is important that the part be distinct and reflect the actor, with neither the role nor the player overwhelming the other.